1. Field of the Invention
The present invention generally relates to agricultural seed planting implements and to the seed meter assemblies of such implements, and more particularly to the air supply of vacuum systems of the seed meter assemblies.
2. Description of the Related Art
Farmers utilize a wide variety of seed planting implements, including seed drills and planters. In a known type of planting implement, seed planting or row units are attached to a toolbar extending transverse to the direction of planting. The toolbar is coupled to a tractor or other work vehicle suitable for pulling the planting implement along a field that is to be seeded to a crop. Each planting unit includes a ground penetrating assembly, often including one or more discs, for opening a seed trench or furrow in the ground as the planting implement is pulled across a field. Components of the ground penetrating assembly shape the bottom and sides of the seed trench, and a seed metering device provides individual seeds at a controlled rate for deposit in the seed trench. Furrow closing components of each row unit close the seed trench in a controlled manner.
Seed metering devices on seed planting implements receive bulk quantities of seeds from a seed hopper or bin, individualize the seeds and dispense the seeds at precise intervals for deposit into the seed trench. Different types of seed metering devices and systems are known. In a known type of seed meter, a seed disc defines seed cells at the periphery thereof. The seed disc is rotated in a controlled manner, including passing along a seed reservoir containing a small quantity of seeds. Vacuum is applied against the opposite side of the seed disc from the seed reservoir and individual seeds are drawn into or against the seed cells from the seed reservoir. Individual seeds are carried by the seed disk to a point in its path of rotation at which the vacuum is terminated. The individual seeds are then dropped into a seed tube or channel for placement into the seed trench formed in the ground.
Effective and accurate operation of a seed metering device as described above requires a steady, uninterrupted flow of air into the system. Operation in a field environment presents challenges to the continuous, effective operation of a seed metering system in that farm implements traversing a field raise considerable dust and debris. In the immediate area of the seed metering device, the seed planting or row units raise additional dirt and debris while opening the seed trench and closing the seed trench in front of and behind the seed metering device. Further, the row units can be relatively closely spaced side-by-side so that each row unit contributes to the dirty environment not only for the metering device operating on it, but also for the metering devices operating on other row units near to it. Environmental conditions such as wind and rain, soil condition and soil type also contribute to the generation of a difficult to control, dirty environment. Known air supply systems for seed metering devices have included air inlets that are prone to plugging or obstruction. Inadequate air supply can cause less effective operation of the seed metering device, resulting in missed seeds, seed bunching or even complete failure of the seed metering device.
What is needed in the art is an air supply system for a seed metering device that is less prone to plugging or obstruction yet simple in design and easy to service.